I'd basically use games to benchmark my GPU performance, try out multiple games and try it with low end settings, normal and high end. Then just take not of the FPS (You can use Fraps to overlay that in-game) and check how responsive the game is. Then just swap out the GPU (or use a different computer with the different hardware) and try again and compare.

It would be a smart move to use the most recent games as they most likely have support for the newer GPU's and try to take the most out of the available hardware. Games like Skyrim, Resident Evil Revelations, Assassins Creed 3 and such would be a good place to start.

Oh and when I say high end settings I mean turn up everything to the absolute max (even if it laggs a lot)

Basically, if you're testing only GPU performance, it doesn't matter what parts you're using elsewhere as long as they're the same for every test.

Ideally, you want to use the fastest parts available, just so that bottle necking doesn't occur, which could corrupt results.

Overall, as long as the graphics card is all that is being changed then you don't need to worry about the other parts, it's still possible to tell the difference between the cards.

Those specs listed are pointless for testing a 5450 though, you want to make sure that all your parts are somewhat balanced, you'd be better off spending all the money from the CPU on a video card and only using an i3, in the case of the second scenario

Yes 5450 is a pointless test on that setup but like i wanted to know would that be a good to test all ATI gpu's , as a lot of tests out there use all sorts of parts from test to test. where as if you was to use a set up like that it would give = results all round wont it? as there is no factor to cpu memory mb as they all stay the same?? or im i wrong?